When researchers watched students through three hours of study, the students were distracted 35 times on average (Calderwood et al., 2014, as cited in Biwer et al., 2023). That is about one interruption every five minutes.
One widely recommended fix is the Pomodoro Technique. You study for about 25 minutes without distraction, take a 5-minute break, and after four rounds take a longer one. Unlike the strategies earlier in this series, it does nothing to the material itself. It only decides when you stop. Biwer and colleagues (2023) note that study-skills books and apps widely recommend the schedule, yet they knew of no empirical test of it.
What a Randomized Test Found
Biwer and colleagues (2023) randomly assigned students at a Dutch university to one of three break schedules. One group took breaks whenever they chose. A second took 6 minutes after every 24-minute block, the authors’ version of Pomodoro. A third took 3 minutes after every 12. The analysis covered 87 students, each studying their own material in an online environment for one session of up to two hours, during the 2020 COVID-19 lockdown.
Students who chose their own breaks took fewer and longer ones, studying in blocks of about 44 minutes. Just before their breaks, they reported more fatigue and distraction than both timed groups. They also reported less concentration and less motivation to start again, and they rated the work as harder.
The groups did not differ in mental effort or in how much of their planned work they said they finished. The authors suggest the timed groups were more efficient, but their data give that only weak support: total study time did not differ reliably, and the 24-minute group studied longest. The two timed schedules were close on almost everything. Students on the 12-minute schedule felt somewhat more interested before their breaks, and nothing in the study singles out 25 minutes.
What the Evidence Cannot Tell You
Apart from logged study and break times, every outcome was self-reported. Students worked on their own tasks, from watching a lecture to writing a thesis, so there was no learning test, and neither retention nor transfer was measured.
The self-regulated group also studied in much longer blocks, so the authors could not tell whether their greater fatigue came from deciding when to stop or simply from studying longer without a pause. And more students dropped out of the timed groups. Those who stayed may have been the ones who liked the schedule, which could flatter it.
A 2025 scoping review by Ogut mapped 32 studies of the technique and rated the overall certainty of the evidence as moderate to low. Most of the studies were observational or conceptual. Its comparison with self-paced breaks rests on what it calls three randomized controlled trials with 87 participants (p. 1). Those numbers, and the 24- and 12-minute schedules, match the three groups of Biwer’s single trial, so the review appears to add no independent second test. It found no study in anatomy, its target subject. It cites one experiment in which students trained in the technique did better on tests, a study known here only through the review, and it says the evidence mostly reflects short-term outcomes rather than long-term retention.
Why a Timer Might Help
Biwer and colleagues draw mainly on an account of distraction. On the opportunity-cost model (Kurzban et al., 2013, as cited in Biwer et al., 2023), effort feels more costly the more attractive the best alternative is, such as the phone beside you. A break that is guaranteed soon lets you defer that pull. One student in Biwer’s study put it this way: “It’s only 12 min, I’ll do this in the next break” (p. 363). A second idea is that deciding when to stop is itself a small ongoing load. The timed groups’ reports fit both ideas, but because their blocks were also shorter, the study cannot say which one, if either, explains the difference.
The same schedule can also get in the way. Some of Biwer’s students found the imposed breaks broke their flow and made it hard to get back into the material, and some felt forced to stop. Ogut adds, without testing it, that fixed timing may interrupt work that needs prolonged concentration or spatial reasoning, and that heavy reliance on a timer might cause anxiety.
Using It Without Overselling It
If your problem is starting, or staying off your phone, a timer is cheap to try. Set the schedule before you begin, so that when to stop is already decided. That may be part of why the timed groups felt better, though their shorter blocks could also explain the gap. When something tempts you mid-block, push it to the break, as Biwer’s students described doing. Block length is yours to choose: the 12- and 24-minute schedules came out about the same, and the authors suggest, without testing it, that the best length may depend on the task. Treat the timer as a default, so a hard problem can run past it. And fill the blocks with the strategies that build memory, because a focused 25 minutes of rereading is still rereading.
If you design courses or online modules, Biwer’s authors suggest the online system’s own break schedule may have helped students working alone during lockdown. Offering one is cheap. Making it mandatory risks the problems Biwer’s students reported, broken flow and more dropouts, and nothing here shows it raises exam scores.
What This Looked Like for Me
By my fourth year of medical school my study sessions leaked time everywhere. I would sit down meaning to review for two hours and surface ninety minutes later having done maybe half of it, the rest lost to a phone I kept telling myself I’d check once. I knew what to study. My trouble was staying in the chair.
Timed blocks helped with that specific problem. With the break coming, it was easier to leave the phone alone. The sessions felt less draining, and I stopped finishing them with the scattered feeling that used to push me to quit early.
I did not retain anatomy or pharmacology because of a timer. The timer got me to the point where I could do retrieval practice and spaced review consistently, and work through problems, but I changed too much at once to separate its share. I also broke the rule when it got in the way. If I was midway through a complex case when the timer went off, I finished the thought.
The Core Lesson
In the one randomized test in the sources behind this series, students on a timer reported less fatigue and distraction than students who chose their own breaks. That study measured no learning, so it cannot say whether the focus became better memory, and no randomized test of that step exists in these sources. Focus plausibly helps the strategies that do build memory, such as elaboration and self-explanation, but no study here tested that link.
Next, we turn from managing your attention to monitoring your own understanding: metacognition.
This post is part of a series on the science of learning. Each post covers one evidence-based principle and how to apply it to your own studying. Follow us on Instagram @acemeded to keep up with future blog posts and related content.
References
Biwer, F., Wiradhany, W., oude Egbrink, M. G. A., & de Bruin, A. B. H. (2023). Understanding effort regulation: Comparing ‘Pomodoro’ breaks and self-regulated breaks. British Journal of Educational Psychology, 93(Suppl. 2), 353–367. https://doi.org/10.1111/bjep.12593
Ogut, E. (2025). Assessing the efficacy of the Pomodoro technique in enhancing anatomy lesson retention during study sessions: A scoping review. BMC Medical Education, 25, Article 1440. https://doi.org/10.1186/s12909-025-08001-0
